Divide the dough into 10 equal portions, and roll each portion into a ball.
Flatten the dough with a rolling pin.
Add a piece of mochi in the centre of the dough.
Next, add the red bean paste filling on top of the mochi piece, gather up the dough, and pinch the seams together.
Place the dough seam-side down on a baking tray lined with parchment paper.
Press the dough gently to flatten a little.
Repeat with the remainder and cover the buns with a cloth. Let the buns rise in a warm location until puffy and doubled in size.
Towards the end of the proofing time, preheat oven to 350°F/177°C.
Brush the tops of the buns with a little milk.
Bake the buns at 350°F/177°C for 18-20 minutes, or until lightly golden brown on top (if it's browning too quickly, cover with aluminum foil halfway).
Let the buns completely cool before adding in the whipped cream.